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<head><meta charset="utf-8"><title>design meeting 2020.04.28 · wg-traits · Zulip Chat Archive</title></head>
<h2>Stream: <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/index.html">wg-traits</a></h2>
<h3>Topic: <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html">design meeting 2020.04.28</a></h3>

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<a name="195618205"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195618205" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195618205">(Apr 28 2020 at 20:00)</a>:</h4>
<p>Hi <span class="user-group-mention" data-user-group-id="692">@WG-traits</span></p>



<a name="195618236"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195618236" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195618236">(Apr 28 2020 at 20:00)</a>:</h4>
<p>Meeting time</p>



<a name="195618315"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195618315" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195618315">(Apr 28 2020 at 20:00)</a>:</h4>
<p>We don't really have a lot on the agenda today</p>



<a name="195618355"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195618355" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195618355">(Apr 28 2020 at 20:00)</a>:</h4>
<p>(Everything that is there, I've literally added in the past couple hours)</p>



<a name="195618377"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195618377" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195618377">(Apr 28 2020 at 20:01)</a>:</h4>
<p>But, let's start with announcements</p>



<a name="195618391"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195618391" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195618391">(Apr 28 2020 at 20:01)</a>:</h4>
<p>And sprint progress</p>



<a name="195618431"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195618431" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Areredify <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195618431">(Apr 28 2020 at 20:01)</a>:</h4>
<p>link pls</p>



<a name="195618444"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195618444" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> detrumi <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195618444">(Apr 28 2020 at 20:01)</a>:</h4>
<p><a href="https://hackmd.io/nrhN5A8sR2eY9UdfJTKcJg?both" title="https://hackmd.io/nrhN5A8sR2eY9UdfJTKcJg?both">https://hackmd.io/nrhN5A8sR2eY9UdfJTKcJg?both</a></p>



<a name="195618528"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195618528" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195618528">(Apr 28 2020 at 20:02)</a>:</h4>
<p>So, 2 weeks left in the sprint</p>



<a name="195618572"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195618572" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195618572">(Apr 28 2020 at 20:02)</a>:</h4>
<p>There were 5 PRs merged in the last week</p>



<a name="195618597"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195618597" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195618597">(Apr 28 2020 at 20:02)</a>:</h4>
<p>Some work on the book :)</p>



<a name="195618605"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195618605" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195618605">(Apr 28 2020 at 20:02)</a>:</h4>
<p>So, I reviewed the const generics PR and we are working out a list of test cases, preparing to land</p>



<a name="195618622"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195618622" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195618622">(Apr 28 2020 at 20:02)</a>:</h4>
<p>Some pretty diagrams from <span class="user-mention" data-user-id="116009">@nikomatsakis</span></p>



<a name="195618659"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195618659" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195618659">(Apr 28 2020 at 20:02)</a>:</h4>
<p>At this rate, I'm wondering if it's worth just adding const generics in the rustc PR</p>



<a name="195618721"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195618721" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195618721">(Apr 28 2020 at 20:03)</a>:</h4>
<p>interesting. quite possible.</p>



<a name="195618757"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195618757" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195618757">(Apr 28 2020 at 20:03)</a>:</h4>
<p>I don't think it'll make a ton of difference either way</p>



<a name="195618765"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195618765" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Areredify <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195618765">(Apr 28 2020 at 20:03)</a>:</h4>
<p>Should we discuss const types while we are at it (do we need them for mvp?)</p>



<a name="195618792"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195618792" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195618792">(Apr 28 2020 at 20:03)</a>:</h4>
<p>ah interesting</p>



<a name="195618799"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195618799" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195618799">(Apr 28 2020 at 20:04)</a>:</h4>
<p>Consts weren't part of the mvp</p>



<a name="195618961"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195618961" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195618961">(Apr 28 2020 at 20:04)</a>:</h4>
<p>If there's something to discuss here, let's add it to the agenda for today</p>



<a name="195618964"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195618964" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195618964">(Apr 28 2020 at 20:04)</a>:</h4>
<p>I think we should leave consts out</p>



<a name="195618991"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195618991" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195618991">(Apr 28 2020 at 20:04)</a>:</h4>
<p>but yes, let's discuss <span aria-label="+1" class="emoji emoji-1f44d" role="img" title="+1">:+1:</span></p>



<a name="195619005"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195619005" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195619005">(Apr 28 2020 at 20:04)</a>:</h4>
<p>I'm looking over the other items</p>



<a name="195619015"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195619015" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195619015">(Apr 28 2020 at 20:05)</a>:</h4>
<p>but let's get through annoucements first</p>



<a name="195619026"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195619026" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> detrumi <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195619026">(Apr 28 2020 at 20:05)</a>:</h4>
<p>Would make it harder to change const handling later, if needed</p>



<a name="195619077"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195619077" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195619077">(Apr 28 2020 at 20:05)</a>:</h4>
<blockquote>
<div class="codehilite"><pre><span></span><code>* explore converting semantic-to-syntactic equality
</code></pre></div>


</blockquote>



<a name="195619086"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195619086" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195619086">(Apr 28 2020 at 20:05)</a>:</h4>
<p><span class="user-mention" data-user-id="251766">@Areredify</span> opened a PR here, right?</p>



<a name="195619116"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195619116" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Areredify <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195619116">(Apr 28 2020 at 20:05)</a>:</h4>
<p>Yes, I did do that</p>



<a name="195619117"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195619117" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195619117">(Apr 28 2020 at 20:05)</a>:</h4>
<p>maybe next on my review list :)</p>



<a name="195619127"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195619127" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195619127">(Apr 28 2020 at 20:05)</a>:</h4>
<p>yes there's a WIP pr</p>



<a name="195619245"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195619245" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195619245">(Apr 28 2020 at 20:06)</a>:</h4>
<p>also <span class="user-mention" data-user-id="125131">@detrumi</span> opened a PR around impl trait generics</p>



<a name="195619262"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195619262" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195619262">(Apr 28 2020 at 20:06)</a>:</h4>
<p>which things landed, do we have updates and shout-outs for those?</p>



<a name="195619313"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195619313" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Areredify <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195619313">(Apr 28 2020 at 20:06)</a>:</h4>
<p>It's only for aliases types as of now, and it fails on 1 test</p>



<a name="195619335"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195619335" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195619335">(Apr 28 2020 at 20:07)</a>:</h4>
<p>also, there is work on built-in traits, I'm not sure which bullet point that falls under...</p>



<a name="195619348"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195619348" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> detrumi <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195619348">(Apr 28 2020 at 20:07)</a>:</h4>
<p><span class="user-mention silent" data-user-id="116009">nikomatsakis</span> <a href="#narrow/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28/near/195619245" title="#narrow/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28/near/195619245">said</a>:</p>
<blockquote>
<p>also <span class="user-mention silent" data-user-id="125131">detrumi</span> opened a PR around impl trait generics</p>
</blockquote>
<p>Yeah, though at this point I'm not sure that was the right thing to start with</p>



<a name="195619409"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195619409" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Areredify <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195619409">(Apr 28 2020 at 20:07)</a>:</h4>
<p>is work on <code>Unsize</code> stalled on that refactoring in rustc you were talking about?</p>



<a name="195619432"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195619432" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195619432">(Apr 28 2020 at 20:07)</a>:</h4>
<p>hmm</p>



<a name="195619442"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195619442" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195619442">(Apr 28 2020 at 20:08)</a>:</h4>
<p>Is <code>Unsize</code> work stalled?</p>



<a name="195619490"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195619490" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195619490">(Apr 28 2020 at 20:08)</a>:</h4>
<p>no, but it'd be good for me to take down as two work items to write out those two things and point you at them</p>



<a name="195619551"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195619551" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195619551">(Apr 28 2020 at 20:08)</a>:</h4>
<p>in particular</p>



<a name="195619564"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195619564" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Areredify <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195619564">(Apr 28 2020 at 20:08)</a>:</h4>
<p>I was somewhat absent for the past week (or two), but now im going strong again <span aria-label="muscle" class="emoji emoji-1f4aa" role="img" title="muscle">:muscle:</span></p>



<a name="195619585"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195619585" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195619585">(Apr 28 2020 at 20:08)</a>:</h4>
<p>I can create a chalk issue and point at the relevant code in rustc that implemented the <code>Unsize</code> check,</p>



<a name="195619612"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195619612" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195619612">(Apr 28 2020 at 20:08)</a>:</h4>
<p>I can do that after this meeting readily enough</p>



<a name="195619631"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195619631" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195619631">(Apr 28 2020 at 20:09)</a>:</h4>
<p>I will also open a rustc issue about the refactoring</p>



<a name="195619673"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195619673" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195619673">(Apr 28 2020 at 20:09)</a>:</h4>
<p>I think that fits .. well  .. it doesn't really fit :) but sort of fits within the "align rustc/chalk" heading</p>



<a name="195619690"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195619690" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195619690">(Apr 28 2020 at 20:09)</a>:</h4>
<p>Totally fits</p>



<a name="195619695"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195619695" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195619695">(Apr 28 2020 at 20:09)</a>:</h4>
<p><span class="user-mention silent" data-user-id="116009">nikomatsakis</span> <a href="#narrow/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28/near/195619631" title="#narrow/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28/near/195619631">said</a>:</p>
<blockquote>
<p>I will also open a rustc issue about the refactoring</p>
</blockquote>
<p>maybe I already did, I forget sometimes how many issues I've opened over the years :P</p>



<a name="195619741"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195619741" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195619741">(Apr 28 2020 at 20:09)</a>:</h4>
<p>sometimes I stumble on an issue and I'm like "oh, yeah, this is perfect"</p>



<a name="195619837"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195619837" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195619837">(Apr 28 2020 at 20:10)</a>:</h4>
<p>Okay, any other announcements?</p>



<a name="195619887"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195619887" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195619887">(Apr 28 2020 at 20:10)</a>:</h4>
<p>so where does the work on <code>Sized</code> trait and <code>Copy</code> trait etc go?</p>



<a name="195619901"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195619901" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195619901">(Apr 28 2020 at 20:10)</a>:</h4>
<p>we landed the "basic builtin types" too, this week, I think, right?</p>



<a name="195619918"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195619918" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195619918">(Apr 28 2020 at 20:10)</a>:</h4>
<p>I'd be curious to sync up on built-in traits and types and what the next steps are</p>



<a name="195619935"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195619935" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195619935">(Apr 28 2020 at 20:10)</a>:</h4>
<p>yes</p>



<a name="195619962"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195619962" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195619962">(Apr 28 2020 at 20:10)</a>:</h4>
<p>I guess that was directed towards rustc integration MVP</p>



<a name="195619979"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195619979" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195619979">(Apr 28 2020 at 20:11)</a>:</h4>
<p><a href="https://github.com/rust-lang/chalk/issues/368" title="https://github.com/rust-lang/chalk/issues/368">https://github.com/rust-lang/chalk/issues/368</a> this issue should be updated</p>



<a name="195620008"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195620008" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195620008">(Apr 28 2020 at 20:11)</a>:</h4>
<p><a href="https://github.com/rust-lang/chalk/issues/363" title="https://github.com/rust-lang/chalk/issues/363">https://github.com/rust-lang/chalk/issues/363</a></p>



<a name="195620024"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195620024" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195620024">(Apr 28 2020 at 20:11)</a>:</h4>
<p>that issue is for builtin traits</p>



<a name="195620078"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195620078" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195620078">(Apr 28 2020 at 20:11)</a>:</h4>
<p>so which of these boxes should be checked</p>



<a name="195620155"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195620155" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195620155">(Apr 28 2020 at 20:12)</a>:</h4>
<p>seems like, after <a href="https://github.com/rust-lang/chalk/pull/413" title="https://github.com/rust-lang/chalk/pull/413">https://github.com/rust-lang/chalk/pull/413</a>, we have sized/copy/clone?</p>



<a name="195620164"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195620164" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Areredify <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195620164">(Apr 28 2020 at 20:12)</a>:</h4>
<p><code>Sized</code> and <code>Copy</code> are up to date with types that are implemented in chalk (after merging <span class="user-mention" data-user-id="281572">@marmeladema</span> 's pr, that is), <code>Drop</code> is finished I think.</p>



<a name="195620191"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195620191" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195620191">(Apr 28 2020 at 20:12)</a>:</h4>
<p>ok, not clone?</p>



<a name="195620218"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195620218" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Areredify <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195620218">(Apr 28 2020 at 20:12)</a>:</h4>
<p>Oh, and <code>Clone</code> too</p>



<a name="195620230"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195620230" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195620230">(Apr 28 2020 at 20:13)</a>:</h4>
<p>scalars and tuples are added</p>



<a name="195620240"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195620240" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> marmeladema <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195620240">(Apr 28 2020 at 20:13)</a>:</h4>
<p>Right now, everything that is Copy is Clone</p>



<a name="195620267"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195620267" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> marmeladema <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195620267">(Apr 28 2020 at 20:13)</a>:</h4>
<p>(sorry to jump in)</p>



<a name="195620369"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195620369" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195620369">(Apr 28 2020 at 20:13)</a>:</h4>
<p>I think the only thing missing from <span class="user-mention" data-user-id="281572">@marmeladema</span>'s PR is that we should add a test for that</p>



<a name="195620438"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195620438" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Areredify <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195620438">(Apr 28 2020 at 20:14)</a>:</h4>
<p>So I wouldn't tick them off as "complete" until we finish adding all the types in chalk</p>



<a name="195620442"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195620442" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195620442">(Apr 28 2020 at 20:14)</a>:</h4>
<p>which I was about to leave as a comment</p>



<a name="195620446"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195620446" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195620446">(Apr 28 2020 at 20:14)</a>:</h4>
<p>Yep, that's close</p>



<a name="195620505"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195620505" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> marmeladema <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195620505">(Apr 28 2020 at 20:14)</a>:</h4>
<p>Ok i'll add tests for that</p>



<a name="195620511"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195620511" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195620511">(Apr 28 2020 at 20:14)</a>:</h4>
<p>(but I'm not sure why you say that everything which is copy is clone, <span class="user-mention" data-user-id="281572">@marmeladema</span>, not sure that will "fall out", I wouldn't think so, unless we have some suitable code)</p>



<a name="195620635"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195620635" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195620635">(Apr 28 2020 at 20:15)</a>:</h4>
<p>the problem I guess with the two issues is that</p>



<a name="195620643"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195620643" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195620643">(Apr 28 2020 at 20:15)</a>:</h4>
<p>really support is a kind of "matrix"</p>



<a name="195620664"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195620664" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195620664">(Apr 28 2020 at 20:15)</a>:</h4>
<p>maybe we should try to write that out..</p>



<a name="195620696"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195620696" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195620696">(Apr 28 2020 at 20:15)</a>:</h4>
<p>That would be helpful I think</p>



<a name="195620780"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195620780" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> marmeladema <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195620780">(Apr 28 2020 at 20:16)</a>:</h4>
<p>I might have used the wrong terminology because all of this is totally new area for me but: <a href="https://github.com/rust-lang/chalk/blob/master/chalk-solve/src/clauses/builtin_traits/clone.rs#L16" title="https://github.com/rust-lang/chalk/blob/master/chalk-solve/src/clauses/builtin_traits/clone.rs#L16">https://github.com/rust-lang/chalk/blob/master/chalk-solve/src/clauses/builtin_traits/clone.rs#L16</a> it pushes the same clause for the Clone trait as for the Copy trait</p>



<a name="195620808"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195620808" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195620808">(Apr 28 2020 at 20:16)</a>:</h4>
<p>i.e., there is like</p>
<table>
<thead>
<tr>
<th>trait</th>
<th>scalar types</th>
<th>closure types</th>
</tr>
</thead>
<tbody>
<tr>
<td>Basic support</td>
<td><span aria-label="check" class="emoji emoji-2705" role="img" title="check">:check:</span></td>
<td><span aria-label="grey question" class="emoji emoji-2754" role="img" title="grey question">:grey_question:</span></td>
</tr>
<tr>
<td>Copy</td>
<td><span aria-label="check" class="emoji emoji-2705" role="img" title="check">:check:</span></td>
<td><span aria-label="grey question" class="emoji emoji-2754" role="img" title="grey question">:grey_question:</span></td>
</tr>
</tbody>
</table>



<a name="195620816"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195620816" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195620816">(Apr 28 2020 at 20:16)</a>:</h4>
<p>or whatever</p>



<a name="195620846"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195620846" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195620846">(Apr 28 2020 at 20:16)</a>:</h4>
<p>ok, that's exactly the line I was looking for, thanks <span class="user-mention" data-user-id="281572">@marmeladema</span></p>



<a name="195620912"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195620912" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195620912">(Apr 28 2020 at 20:17)</a>:</h4>
<p>(I think part of that is <em>where</em> these impls are. Whether they are builtin, in libcore, or not)</p>



<a name="195620964"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195620964" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195620964">(Apr 28 2020 at 20:18)</a>:</h4>
<p>yep</p>



<a name="195621001"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195621001" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195621001">(Apr 28 2020 at 20:18)</a>:</h4>
<p>Anyways, maybe we should defer this to after the meeting?</p>



<a name="195621004"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195621004" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195621004">(Apr 28 2020 at 20:18)</a>:</h4>
<p>that would be a super useful chart really</p>



<a name="195621016"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195621016" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195621016">(Apr 28 2020 at 20:18)</a>:</h4>
<p>18 minutes in</p>



<a name="195621021"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195621021" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195621021">(Apr 28 2020 at 20:18)</a>:</h4>
<p>yes, let's make an issue</p>



<a name="195621024"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195621024" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195621024">(Apr 28 2020 at 20:18)</a>:</h4>
<p>to work it out</p>



<a name="195621033"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195621033" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195621033">(Apr 28 2020 at 20:18)</a>:</h4>
<p>it could go in the chalk book</p>



<a name="195621046"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195621046" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195621046">(Apr 28 2020 at 20:18)</a>:</h4>
<p>Agreed</p>



<a name="195621067"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195621067" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195621067">(Apr 28 2020 at 20:18)</a>:</h4>
<p>I'm doing that</p>



<a name="195621076"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195621076" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195621076">(Apr 28 2020 at 20:18)</a>:</h4>
<p>feel free to take us to another topic</p>



<a name="195621081"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195621081" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195621081">(Apr 28 2020 at 20:18)</a>:</h4>
<p>Anyways, moving on</p>



<a name="195621103"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195621103" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195621103">(Apr 28 2020 at 20:18)</a>:</h4>
<p>We already discussed this a bit, but release</p>



<a name="195621151"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195621151" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195621151">(Apr 28 2020 at 20:19)</a>:</h4>
<p>I think we should do a release now</p>



<a name="195621202"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195621202" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> detrumi <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195621202">(Apr 28 2020 at 20:19)</a>:</h4>
<p>Are releases relevant for the rustc integration PR, or do we just want to start asap?</p>



<a name="195621209"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195621209" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195621209">(Apr 28 2020 at 20:19)</a>:</h4>
<p>Well, I have to PR adding <code>Copy</code> derive to chalk interned wrapper types, but after that, we have everything we need</p>



<a name="195621221"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195621221" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195621221">(Apr 28 2020 at 20:19)</a>:</h4>
<p>yes, it is</p>



<a name="195621246"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195621246" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195621246">(Apr 28 2020 at 20:19)</a>:</h4>
<p>We have to have a release on <a href="http://crates.io" title="http://crates.io">crates.io</a> for rustc PR</p>



<a name="195621396"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195621396" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195621396">(Apr 28 2020 at 20:20)</a>:</h4>
<p>that reminds me</p>



<a name="195621401"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195621401" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195621401">(Apr 28 2020 at 20:20)</a>:</h4>
<p>So, unless anyone has any objections, we should do that in the next day or two?</p>



<a name="195621419"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195621419" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195621419">(Apr 28 2020 at 20:20)</a>:</h4>
<p>the tracing Pr looked great but I was not sure if we want to add tracing as a pre-req for rustc</p>



<a name="195621437"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195621437" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195621437">(Apr 28 2020 at 20:20)</a>:</h4>
<p>(and I think we should perhaps try to align chalk/rustc logging, even? though not necessarily)</p>



<a name="195621457"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195621457" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195621457">(Apr 28 2020 at 20:21)</a>:</h4>
<p>I have no objection to issuing a release, in any case</p>



<a name="195621459"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195621459" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195621459">(Apr 28 2020 at 20:21)</a>:</h4>
<p>mmm, not sure</p>



<a name="195621486"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195621486" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> detrumi <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195621486">(Apr 28 2020 at 20:21)</a>:</h4>
<p>tracing can just output normal logging that rustc accepts</p>



<a name="195621495"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195621495" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195621495">(Apr 28 2020 at 20:21)</a>:</h4>
<p>I think that's something easily done in a followup PR</p>



<a name="195621507"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195621507" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195621507">(Apr 28 2020 at 20:21)</a>:</h4>
<p>I also happen to thikn it'd be great if we used tracing <em>in</em> rustc, though <span class="user-mention silent" data-user-id="119009">eddyb</span>'s comments the other day gave me a bit of pause that maybe it doesn't do all I had hoped it would do</p>



<a name="195621544"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195621544" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195621544">(Apr 28 2020 at 20:22)</a>:</h4>
<p>Which comments?</p>



<a name="195621664"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195621664" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> detrumi <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195621664">(Apr 28 2020 at 20:22)</a>:</h4>
<p>I'm assuming that tracing will need some more work to get it fully working for rustc, and it's not actually that important for the first integration</p>



<a name="195621722"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195621722" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195621722">(Apr 28 2020 at 20:23)</a>:</h4>
<p>Right</p>



<a name="195621760"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195621760" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> detrumi <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195621760">(Apr 28 2020 at 20:23)</a>:</h4>
<p>(might also require more buy-in from other rustc devs)</p>



<a name="195621762"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195621762" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195621762">(Apr 28 2020 at 20:23)</a>:</h4>
<p>Okay, for release I'll talk with <span class="user-mention" data-user-id="116009">@nikomatsakis</span> after the meeting (sync or async) and get that done</p>



<a name="195621844"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195621844" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195621844">(Apr 28 2020 at 20:24)</a>:</h4>
<p>Niko is MIA</p>



<a name="195621882"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195621882" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195621882">(Apr 28 2020 at 20:24)</a>:</h4>
<p>Sorry, I'm back :)</p>



<a name="195621909"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195621909" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195621909">(Apr 28 2020 at 20:24)</a>:</h4>
<p><span class="user-mention silent" data-user-id="232957">Jack Huey</span> <a href="#narrow/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28/near/195621544" title="#narrow/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28/near/195621544">said</a>:</p>
<blockquote>
<p>Which comments?</p>
</blockquote>
<p>I meant that maybe it doesn't support nested hierarchical stuff as well as I hoped</p>



<a name="195621934"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195621934" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195621934">(Apr 28 2020 at 20:25)</a>:</h4>
<p>Oh, I actually don't know</p>



<a name="195621936"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195621936" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195621936">(Apr 28 2020 at 20:25)</a>:</h4>
<p><span class="user-mention silent" data-user-id="125131">detrumi</span> <a href="#narrow/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28/near/195621664" title="#narrow/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28/near/195621664">said</a>:</p>
<blockquote>
<p>I'm assuming that tracing will need some more work to get it fully working for rustc, and it's not actually that important for the first integration</p>
</blockquote>
<p>yeah that would be a big job</p>



<a name="195621957"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195621957" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195621957">(Apr 28 2020 at 20:25)</a>:</h4>
<p>my main point is that I don't think we want to add a bunch of deps to rustc willy nilly</p>



<a name="195621986"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195621986" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195621986">(Apr 28 2020 at 20:25)</a>:</h4>
<p>anyway maybe it doesn't matter, and tracing is only one random one</p>



<a name="195622011"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195622011" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195622011">(Apr 28 2020 at 20:25)</a>:</h4>
<p>we should take a moment to look though at the deps as part of the release</p>



<a name="195622013"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195622013" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195622013">(Apr 28 2020 at 20:25)</a>:</h4>
<p>we can do that async</p>



<a name="195622063"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195622063" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195622063">(Apr 28 2020 at 20:26)</a>:</h4>
<p>I looked shortly</p>



<a name="195622073"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195622073" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195622073">(Apr 28 2020 at 20:26)</a>:</h4>
<p>opened <em>document the "built-in trait impls" and where they live</em> <a href="https://github.com/rust-lang-nursery/chalk/issues/416" title="https://github.com/rust-lang-nursery/chalk/issues/416">chalk#416</a> , btw</p>



<a name="195622085"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195622085" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195622085">(Apr 28 2020 at 20:26)</a>:</h4>
<p>Not that much that isn't already there</p>



<a name="195622114"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195622114" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195622114">(Apr 28 2020 at 20:26)</a>:</h4>
<p><code>petgraph</code> was the only "new" one</p>



<a name="195622135"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195622135" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195622135">(Apr 28 2020 at 20:26)</a>:</h4>
<p>okay, let's move on</p>



<a name="195622137"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195622137" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195622137">(Apr 28 2020 at 20:26)</a>:</h4>
<p>hmm, we use petgraph? :)</p>



<a name="195622147"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195622147" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195622147">(Apr 28 2020 at 20:26)</a>:</h4>
<p>in chalk-solve for coherence</p>



<a name="195622158"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195622158" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195622158">(Apr 28 2020 at 20:26)</a>:</h4>
<p>oh</p>



<a name="195622159"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195622159" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195622159">(Apr 28 2020 at 20:27)</a>:</h4>
<p>how random</p>



<a name="195622161"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195622161" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195622161">(Apr 28 2020 at 20:27)</a>:</h4>
<p>ok</p>



<a name="195622231"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195622231" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195622231">(Apr 28 2020 at 20:27)</a>:</h4>
<p>So, I merged a PR to add link checking for mdbook</p>



<a name="195622259"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195622259" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195622259">(Apr 28 2020 at 20:27)</a>:</h4>
<p>/me goes to get link</p>



<a name="195622329"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195622329" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195622329">(Apr 28 2020 at 20:28)</a>:</h4>
<p>oh, Niko merged</p>



<a name="195622330"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195622330" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195622330">(Apr 28 2020 at 20:28)</a>:</h4>
<p><a href="https://github.com/rust-lang/chalk/pull/408" title="https://github.com/rust-lang/chalk/pull/408">https://github.com/rust-lang/chalk/pull/408</a></p>



<a name="195622331"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195622331" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> detrumi <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195622331">(Apr 28 2020 at 20:28)</a>:</h4>
<p>Right, so the question was whether to block the build on that</p>



<a name="195622358"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195622358" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195622358">(Apr 28 2020 at 20:28)</a>:</h4>
<p>Yeah, so I noticed the latest build is broken</p>



<a name="195622371"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195622371" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> detrumi <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195622371">(Apr 28 2020 at 20:28)</a>:</h4>
<p>answer is yes then?</p>



<a name="195622375"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195622375" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195622375">(Apr 28 2020 at 20:28)</a>:</h4>
<p>Maybe the url was down</p>



<a name="195622388"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195622388" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195622388">(Apr 28 2020 at 20:28)</a>:</h4>
<p>but it's up now</p>



<a name="195622419"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195622419" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195622419">(Apr 28 2020 at 20:28)</a>:</h4>
<p>but that stops the book from building/deploying, as well as docs</p>



<a name="195622431"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195622431" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195622431">(Apr 28 2020 at 20:29)</a>:</h4>
<p>hmm</p>



<a name="195622448"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195622448" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195622448">(Apr 28 2020 at 20:29)</a>:</h4>
<p>maybe I merged prematurely?</p>



<a name="195622455"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195622455" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195622455">(Apr 28 2020 at 20:29)</a>:</h4>
<p>Maybe</p>



<a name="195622467"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195622467" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195622467">(Apr 28 2020 at 20:29)</a>:</h4>
<p>didn't realize it'd be a bit flakey</p>



<a name="195622478"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195622478" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195622478">(Apr 28 2020 at 20:29)</a>:</h4>
<p>we could have it give a "warning" only or something, probably</p>



<a name="195622480"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195622480" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195622480">(Apr 28 2020 at 20:29)</a>:</h4>
<p>This was something I sort of thought about</p>



<a name="195622493"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195622493" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195622493">(Apr 28 2020 at 20:29)</a>:</h4>
<p>but a bit differently</p>



<a name="195622542"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195622542" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195622542">(Apr 28 2020 at 20:29)</a>:</h4>
<p>I think we should probably make it fail the build, but after deploying docs and book</p>



<a name="195622621"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195622621" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195622621">(Apr 28 2020 at 20:30)</a>:</h4>
<p>or like release, if we do that,</p>



<a name="195622640"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195622640" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> detrumi <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195622640">(Apr 28 2020 at 20:30)</a>:</h4>
<p>Wait, so is <code>Install mdbook-linkcheck</code> failing? How is that more flaky than <code>Install mdbook</code>?</p>



<a name="195622703"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195622703" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195622703">(Apr 28 2020 at 20:30)</a>:</h4>
<p>No</p>



<a name="195622716"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195622716" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195622716">(Apr 28 2020 at 20:30)</a>:</h4>
<p>"Run Chalk book"</p>



<a name="195622724"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195622724" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195622724">(Apr 28 2020 at 20:30)</a>:</h4>
<div class="codehilite"><pre><span></span><code>error: Unable to retrieve &quot;https://dl.acm.org/citation.cfm?id=868380&quot;: https://dl.acm.org/citation.cfm?id=868380: timed out

    ┌── bibliography.md:20:1 ───
    │
 20 │ [&quot;A proof procedure for the logic of Hereditary Harrop formulas&quot;](https://dl.acm.org/citation.cfm?id=868380),
    │ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ https://dl.acm.org/citation.cfm?id=868380: timed out
    │
</code></pre></div>



<a name="195622748"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195622748" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> detrumi <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195622748">(Apr 28 2020 at 20:31)</a>:</h4>
<p>Oh lol</p>



<a name="195622785"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195622785" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195622785">(Apr 28 2020 at 20:31)</a>:</h4>
<p>Basically, I brought this up so we should decide one of:</p>



<a name="195622837"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195622837" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195622837">(Apr 28 2020 at 20:31)</a>:</h4>
<p>1) This doesn't matter<br>
2) We should fully revert PR for now<br>
3) We should make this check-only</p>



<a name="195622928"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195622928" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195622928">(Apr 28 2020 at 20:32)</a>:</h4>
<p>I'd be inclined to go with check-only, if that's easy to do</p>



<a name="195622938"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195622938" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195622938">(Apr 28 2020 at 20:32)</a>:</h4>
<p>I'm not 100% sure what check-only means tbh</p>



<a name="195622957"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195622957" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195622957">(Apr 28 2020 at 20:32)</a>:</h4>
<p>do you mean "only do it on PR builds" and not "master branch builds"?</p>



<a name="195622972"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195622972" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195622972">(Apr 28 2020 at 20:32)</a>:</h4>
<p>which btw makes some sense to me :)</p>



<a name="195623002"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195623002" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195623002">(Apr 28 2020 at 20:33)</a>:</h4>
<p>or do you just mean that, if it fails, we only issue a 'warning' of some kind?</p>



<a name="195623017"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195623017" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195623017">(Apr 28 2020 at 20:33)</a>:</h4>
<p>that's a better idea than what I had</p>



<a name="195623036"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195623036" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195623036">(Apr 28 2020 at 20:33)</a>:</h4>
<p>really either of these seem ok. I think that once things land on the master branch, we shouldn't bother to check URLs</p>



<a name="195623039"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195623039" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> detrumi <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195623039">(Apr 28 2020 at 20:33)</a>:</h4>
<p>If it shows a green checkmark even if the link check fails, then I'm not sure we'll notice it very often</p>



<a name="195623059"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195623059" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195623059">(Apr 28 2020 at 20:33)</a>:</h4>
<p>but we can check PRs..</p>



<a name="195623099"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195623099" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195623099">(Apr 28 2020 at 20:33)</a>:</h4>
<p><span class="user-mention silent" data-user-id="125131">detrumi</span> <a href="#narrow/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28/near/195623039" title="#narrow/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28/near/195623039">said</a>:</p>
<blockquote>
<p>If it shows a green checkmark even if the link check fails, then I'm not sure we'll notice it very often</p>
</blockquote>
<p>agreed, it has to be quite visible</p>



<a name="195623101"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195623101" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195623101">(Apr 28 2020 at 20:33)</a>:</h4>
<p>right, so I <em>was</em> thinking the build "fails" so it's an X, but everything gets built and uploaded</p>



<a name="195623155"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195623155" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195623155">(Apr 28 2020 at 20:34)</a>:</h4>
<p>seems like we can just ignore this on master</p>



<a name="195623163"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195623163" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195623163">(Apr 28 2020 at 20:34)</a>:</h4>
<p>it's either transient</p>



<a name="195623176"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195623176" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195623176">(Apr 28 2020 at 20:34)</a>:</h4>
<p>in which case we don't care</p>



<a name="195623184"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195623184" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195623184">(Apr 28 2020 at 20:34)</a>:</h4>
<p>or it's not, in which case we'll see it on PRs</p>



<a name="195623245"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195623245" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195623245">(Apr 28 2020 at 20:34)</a>:</h4>
<p>Okay, I'll open a PR for that then</p>



<a name="195623255"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195623255" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195623255">(Apr 28 2020 at 20:34)</a>:</h4>
<p>Moving on?</p>



<a name="195623267"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195623267" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195623267">(Apr 28 2020 at 20:35)</a>:</h4>
<blockquote>
<p><code>from_fallible</code> on <code>Interner</code> list-like types</p>
</blockquote>



<a name="195623294"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195623294" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195623294">(Apr 28 2020 at 20:35)</a>:</h4>
<p>Was briefly discussing this with Niko right before the meeting</p>



<a name="195623437"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195623437" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195623437">(Apr 28 2020 at 20:36)</a>:</h4>
<p>But essentially, <code>Substitution</code> does this backwards from the other interned wrapper types</p>



<a name="195623511"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195623511" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195623511">(Apr 28 2020 at 20:36)</a>:</h4>
<p>Where it calls <code>from_fallible</code> from <code>from</code>. And it's up to the <code>Interner</code> to collect the error</p>



<a name="195623549"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195623549" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195623549">(Apr 28 2020 at 20:37)</a>:</h4>
<p>Whereas the other types collect into an intermediate <code>Vec</code> in <code>from_fallible</code> then call <code>from</code></p>



<a name="195623584"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195623584" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195623584">(Apr 28 2020 at 20:37)</a>:</h4>
<p>So, for the rustc integration PR, to do interning, what should we do?</p>



<a name="195623673"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195623673" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195623673">(Apr 28 2020 at 20:38)</a>:</h4>
<p>it seems like</p>



<a name="195623687"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195623687" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195623687">(Apr 28 2020 at 20:38)</a>:</h4>
<p>longer term, it makes sense to me that the 'primitive' operation accommodates <code>Result</code></p>



<a name="195623701"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195623701" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195623701">(Apr 28 2020 at 20:38)</a>:</h4>
<p>but in the short term, I don't care :P</p>



<a name="195623717"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195623717" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195623717">(Apr 28 2020 at 20:38)</a>:</h4>
<p>and I don't necessarily think I would want to refactor rustc right now :)</p>



<a name="195623735"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195623735" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195623735">(Apr 28 2020 at 20:38)</a>:</h4>
<p>that said, the chalk integration PR could just do the "collect to vector" thing in its impl</p>



<a name="195623747"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195623747" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195623747">(Apr 28 2020 at 20:39)</a>:</h4>
<p>but I agree they should be uniform</p>



<a name="195623756"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195623756" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195623756">(Apr 28 2020 at 20:39)</a>:</h4>
<p><span class="user-mention silent" data-user-id="116009">nikomatsakis</span> <a href="#narrow/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28/near/195623735" title="#narrow/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28/near/195623735">said</a>:</p>
<blockquote>
<p>that said, the chalk integration PR could just do the "collect to vector" thing in its impl</p>
</blockquote>
<p>I think this is what I would favor</p>



<a name="195623778"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195623778" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195623778">(Apr 28 2020 at 20:39)</a>:</h4>
<p>Ok, then for now I'm going to change <code>Substitution</code> to do what the other types do</p>



<a name="195623806"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195623806" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195623806">(Apr 28 2020 at 20:39)</a>:</h4>
<p>Or...I could just switch them all around</p>



<a name="195623875"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195623875" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195623875">(Apr 28 2020 at 20:40)</a>:</h4>
<p>Yeah, I'll switch them all to be like Substitution</p>



<a name="195623887"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195623887" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195623887">(Apr 28 2020 at 20:40)</a>:</h4>
<p>right, I was saying that <em>ideally</em> I think we'd switch everything so that the trait offers the fallible alternative</p>



<a name="195623901"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195623901" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195623901">(Apr 28 2020 at 20:40)</a>:</h4>
<p>( and then bridge it in rustc in the 'hacky' way )</p>



<a name="195623919"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195623919" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195623919">(Apr 28 2020 at 20:40)</a>:</h4>
<p>Works for me</p>



<a name="195623953"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195623953" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195623953">(Apr 28 2020 at 20:41)</a>:</h4>
<p>Ok, last thing on the agenda</p>



<a name="195623963"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195623963" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195623963">(Apr 28 2020 at 20:41)</a>:</h4>
<p>Implied bounds</p>



<a name="195623973"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195623973" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195623973">(Apr 28 2020 at 20:41)</a>:</h4>
<p>Sort of fallover from last week</p>



<a name="195623981"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195623981" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195623981">(Apr 28 2020 at 20:41)</a>:</h4>
<p>Did we have something we still needed to talk about?</p>



<a name="195623984"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195623984" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195623984">(Apr 28 2020 at 20:41)</a>:</h4>
<p>(And want to)</p>



<a name="195623997"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195623997" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> detrumi <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195623997">(Apr 28 2020 at 20:41)</a>:</h4>
<p>I was wondering whether they were relevant for opaque types</p>



<a name="195624004"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195624004" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195624004">(Apr 28 2020 at 20:41)</a>:</h4>
<p>hmm, we never did the follow-up around the "external iteration"</p>



<a name="195624017"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195624017" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195624017">(Apr 28 2020 at 20:41)</a>:</h4>
<p>but I don't think now's necessarily the best time for <em>that</em></p>



<a name="195624035"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195624035" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195624035">(Apr 28 2020 at 20:42)</a>:</h4>
<p><span class="user-mention silent" data-user-id="125131">detrumi</span> <a href="#narrow/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28/near/195623997" title="#narrow/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28/near/195623997">said</a>:</p>
<blockquote>
<p>I was wondering whether they were relevant for opaque types</p>
</blockquote>
<p>this is a good question tho</p>



<a name="195624118"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195624118" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195624118">(Apr 28 2020 at 20:42)</a>:</h4>
<p>Can you give a brief overview?</p>



<a name="195624119"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195624119" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195624119">(Apr 28 2020 at 20:42)</a>:</h4>
<p>I think the way to model opaque types is going to be that</p>
<div class="codehilite"><pre><span></span><code>type Foo: Debug
</code></pre></div>


<p>is <code>FromEnv(!Foo: Debug)</code> (which is probably not what we did)</p>



<a name="195624122"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195624122" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195624122">(Apr 28 2020 at 20:42)</a>:</h4>
<p>Haven't followed</p>



<a name="195624170"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195624170" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> detrumi <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195624170">(Apr 28 2020 at 20:43)</a>:</h4>
<p>Right, we do <code>Implemented(!Foo: Debug)</code> currently</p>



<a name="195624178"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195624178" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195624178">(Apr 28 2020 at 20:43)</a>:</h4>
<p>(this is related to the <code>dyn</code> PR that <span class="user-mention" data-user-id="129457">@Florian Diebold</span> opened)</p>



<a name="195624182"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195624182" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195624182">(Apr 28 2020 at 20:43)</a>:</h4>
<p>Yeah, I think that was wrong</p>



<a name="195624184"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195624184" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195624184">(Apr 28 2020 at 20:43)</a>:</h4>
<p>because</p>



<a name="195624193"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195624193" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195624193">(Apr 28 2020 at 20:43)</a>:</h4>
<p>well, two reasons</p>



<a name="195624237"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195624237" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195624237">(Apr 28 2020 at 20:44)</a>:</h4>
<p>the practical one: if you have <code>type Foo: Copy</code>, we wouldn't be able to infer that <code>!Foo: Clone</code></p>



<a name="195624273"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195624273" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195624273">(Apr 28 2020 at 20:44)</a>:</h4>
<p>because we only do that "transitive" reasoning when we can prove <code>FromEnv</code></p>



<a name="195624285"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195624285" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195624285">(Apr 28 2020 at 20:44)</a>:</h4>
<p>conceptually, this is a <code>FromEnv</code> as well -- i.e., <em>somebody else</em> has proven that <code>!Foo: Copy</code>, it's not our job</p>



<a name="195624309"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195624309" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195624309">(Apr 28 2020 at 20:44)</a>:</h4>
<p>that "somebody else" would be the 'well formedness checks'</p>



<a name="195624368"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195624368" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> detrumi <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195624368">(Apr 28 2020 at 20:45)</a>:</h4>
<p>Right, this is very similar to how associated types work, those also have rules with <code>FromEnv</code></p>



<a name="195624416"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195624416" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195624416">(Apr 28 2020 at 20:45)</a>:</h4>
<p>yep, exactly</p>



<a name="195624501"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195624501" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195624501">(Apr 28 2020 at 20:46)</a>:</h4>
<p>/me is lost</p>



<a name="195624526"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195624526" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195624526">(Apr 28 2020 at 20:46)</a>:</h4>
<p>(I'm just pondering now if there are weird cycles that can arise) :)</p>



<a name="195624542"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195624542" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195624542">(Apr 28 2020 at 20:46)</a>:</h4>
<p><span class="user-mention silent" data-user-id="232957">Jack Huey</span> <a href="#narrow/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28/near/195624501" title="#narrow/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28/near/195624501">said</a>:</p>
<blockquote>
<p>/me is lost</p>
</blockquote>
<p>just in general, or some specific part :)</p>



<a name="195624575"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195624575" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195624575">(Apr 28 2020 at 20:46)</a>:</h4>
<p>in general</p>



<a name="195624597"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195624597" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195624597">(Apr 28 2020 at 20:47)</a>:</h4>
<p>not sure what the problems/questions here are</p>



<a name="195624602"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195624602" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195624602">(Apr 28 2020 at 20:47)</a>:</h4>
<p>But that's okay</p>



<a name="195624612"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195624612" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> detrumi <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195624612">(Apr 28 2020 at 20:47)</a>:</h4>
<p>In short, the rules <a href="https://github.com/rust-lang/chalk/blob/master/chalk-solve/src/clauses/program_clauses.rs#L127" title="https://github.com/rust-lang/chalk/blob/master/chalk-solve/src/clauses/program_clauses.rs#L127">here</a> use <code>Implemented</code> instead of <code>FromEnv</code></p>



<a name="195624632"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195624632" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195624632">(Apr 28 2020 at 20:47)</a>:</h4>
<p>ok well there are kind of "two" questions that might be raised</p>



<a name="195624661"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195624661" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195624661">(Apr 28 2020 at 20:47)</a>:</h4>
<p>the first, which is what we were discussing, is that we should remember to think always whether to use <code>Implemented</code> or <code>FromEnv</code></p>



<a name="195624679"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195624679" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195624679">(Apr 28 2020 at 20:48)</a>:</h4>
<p>I think this comes back to the question of names, I think those names are suboptimal :)</p>



<a name="195624726"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195624726" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195624726">(Apr 28 2020 at 20:48)</a>:</h4>
<p>in particular <code>Implemented</code> should really correspond 1-to-1 with an <em>impl</em></p>



<a name="195624733"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195624733" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195624733">(Apr 28 2020 at 20:48)</a>:</h4>
<p>and there is no "impl" here</p>



<a name="195624742"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195624742" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> detrumi <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195624742">(Apr 28 2020 at 20:48)</a>:</h4>
<p><code>HasImpl</code></p>



<a name="195624752"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195624752" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195624752">(Apr 28 2020 at 20:48)</a>:</h4>
<p>right</p>



<a name="195624775"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195624775" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195624775">(Apr 28 2020 at 20:48)</a>:</h4>
<p>and one bit of <em>fallout</em> from using the wrong one is that you don't get transitive reasoning</p>



<a name="195624787"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195624787" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195624787">(Apr 28 2020 at 20:48)</a>:</h4>
<p>because of the design we talked about last time</p>



<a name="195624925"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195624925" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> detrumi <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195624925">(Apr 28 2020 at 20:49)</a>:</h4>
<p>That makes me wonder why we still use <code>Implemented</code> in other places, or if that will run into the same problems</p>



<a name="195624969"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195624969" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195624969">(Apr 28 2020 at 20:50)</a>:</h4>
<p>(i.e., if you know <code>Implemented(X: Copy)</code>, that doesn't let you prove that <code>Implemented(X: Clone)</code>)</p>



<a name="195624995"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195624995" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195624995">(Apr 28 2020 at 20:50)</a>:</h4>
<p>(and the reasons for this are clear enough if you think of it as <code>HasImpl</code>)</p>



<a name="195625031"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195625031" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195625031">(Apr 28 2020 at 20:50)</a>:</h4>
<p><span class="user-mention silent" data-user-id="125131">detrumi</span> <a href="#narrow/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28/near/195624925" title="#narrow/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28/near/195624925">said</a>:</p>
<blockquote>
<p>That makes me wonder why we still use <code>Implemented</code> in other places, or if that will run into the same problems</p>
</blockquote>
<p>yes I think we should audit a bit, I suspect I was wrong, I wans't thinking quite as much about this</p>



<a name="195625061"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195625061" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195625061">(Apr 28 2020 at 20:50)</a>:</h4>
<p>So, <code>HasImpl</code> also is somewhat...weird. Since Chalk generates rules <code>Implemented(T: Foo) :- FromEnv(T: Foo)</code></p>



<a name="195625251"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195625251" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195625251">(Apr 28 2020 at 20:52)</a>:</h4>
<p>Ah, yeah, that's true</p>



<a name="195625259"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195625259" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195625259">(Apr 28 2020 at 20:52)</a>:</h4>
<p>well wait</p>



<a name="195625265"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195625265" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195625265">(Apr 28 2020 at 20:52)</a>:</h4>
<p>that makes sense</p>



<a name="195625286"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195625286" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195625286">(Apr 28 2020 at 20:52)</a>:</h4>
<p>"we can conclude there is an impl for Foo if somebody else has proven it for us"</p>



<a name="195625306"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195625306" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195625306">(Apr 28 2020 at 20:52)</a>:</h4>
<p>an alternative name for <code>FromEnv</code> is <code>FullyImplemented</code></p>



<a name="195625327"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195625327" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195625327">(Apr 28 2020 at 20:52)</a>:</h4>
<p>er, wait</p>



<a name="195625339"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195625339" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195625339">(Apr 28 2020 at 20:52)</a>:</h4>
<p>that was an alternative name for <code>WellFormed(T: Trait)</code></p>



<a name="195625353"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195625353" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195625353">(Apr 28 2020 at 20:53)</a>:</h4>
<p>that <span class="user-mention" data-user-id="131694">@scalexm</span> and I kicked around at some point</p>



<a name="195625366"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195625366" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195625366">(Apr 28 2020 at 20:53)</a>:</h4>
<p>i.e, <code>T: Trait</code> is true but also all the where-clauses on <code>Trait</code></p>



<a name="195625421"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195625421" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195625421">(Apr 28 2020 at 20:53)</a>:</h4>
<p>Names are hard</p>



<a name="195625569"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195625569" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195625569">(Apr 28 2020 at 20:54)</a>:</h4>
<p>Okay, 6 minutes left</p>



<a name="195625584"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195625584" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195625584">(Apr 28 2020 at 20:55)</a>:</h4>
<p>Anything else we need to dicuss</p>



<a name="195625594"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195625594" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Areredify <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195625594">(Apr 28 2020 at 20:55)</a>:</h4>
<p>ⁿᵒᵗ ᵗᵒᵒ ˡᵃᵗᵉ ᵗᵒ ʳᵉⁿᵃᵐᵉ ᵉᵛᵉʳʸᵗʰᶦⁿᵍ</p>



<a name="195625599"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195625599" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195625599">(Apr 28 2020 at 20:55)</a>:</h4>
<p>or anything anybody wants to bring up?</p>



<a name="195625658"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195625658" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195625658">(Apr 28 2020 at 20:55)</a>:</h4>
<p>If not, we can end a little early</p>



<a name="195625661"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195625661" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Areredify <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195625661">(Apr 28 2020 at 20:55)</a>:</h4>
<p>Do consts need types?</p>



<a name="195625679"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195625679" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Areredify <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195625679">(Apr 28 2020 at 20:55)</a>:</h4>
<p>Or did we postpone this one</p>



<a name="195625691"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195625691" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195625691">(Apr 28 2020 at 20:56)</a>:</h4>
<p>We can briefly discuss</p>



<a name="195625731"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195625731" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195625731">(Apr 28 2020 at 20:56)</a>:</h4>
<p>well, it's connected to the rustc integration pr</p>



<a name="195625762"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195625762" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195625762">(Apr 28 2020 at 20:56)</a>:</h4>
<p>what exactly is the question here?</p>



<a name="195625807"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195625807" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Areredify <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195625807">(Apr 28 2020 at 20:56)</a>:</h4>
<p>Is there any need for consts to be typed?</p>



<a name="195625856"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195625856" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195625856">(Apr 28 2020 at 20:57)</a>:</h4>
<p>so, in rustc</p>



<a name="195625872"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195625872" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195625872">(Apr 28 2020 at 20:57)</a>:</h4>
<p>a "constant" includes both its value <em>and</em> a type</p>



<a name="195625875"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195625875" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Areredify <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195625875">(Apr 28 2020 at 20:57)</a>:</h4>
<p>If everything passed to chalk is considered well-fomed, there is no strong need for that</p>



<a name="195625902"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195625902" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195625902">(Apr 28 2020 at 20:57)</a>:</h4>
<p>Oh, I see</p>



<a name="195625927"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195625927" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195625927">(Apr 28 2020 at 20:57)</a>:</h4>
<p>as you can see here, in <a href="https://doc.rust-lang.org/nightly/nightly-rustc/rustc_middle/ty/struct.Const.html" title="https://doc.rust-lang.org/nightly/nightly-rustc/rustc_middle/ty/struct.Const.html"><code>Const</code></a></p>



<a name="195625930"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195625930" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195625930">(Apr 28 2020 at 20:58)</a>:</h4>
<p>Well, we want Chalk to do well-formed checks eventually too</p>



<a name="195625982"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195625982" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195625982">(Apr 28 2020 at 20:58)</a>:</h4>
<p>I think we are probably going to want to do this</p>



<a name="195625990"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195625990" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195625990">(Apr 28 2020 at 20:58)</a>:</h4>
<p>yes, I just clicked the link in the PR comment</p>



<a name="195625998"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195625998" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195625998">(Apr 28 2020 at 20:58)</a>:</h4>
<p>in particular, constants can be "bag of bits"</p>



<a name="195626016"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195626016" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195626016">(Apr 28 2020 at 20:58)</a>:</h4>
<p>I think this is correct to add</p>



<a name="195626039"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195626039" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195626039">(Apr 28 2020 at 20:58)</a>:</h4>
<p>if you loko at <a href="https://doc.rust-lang.org/nightly/nightly-rustc/rustc_middle/mir/interpret/enum.ConstValue.html" title="https://doc.rust-lang.org/nightly/nightly-rustc/rustc_middle/mir/interpret/enum.ConstValue.html"><code>ConstValue</code></a> in rustc</p>



<a name="195626052"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195626052" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195626052">(Apr 28 2020 at 20:58)</a>:</h4>
<p>you see that beyond simple integers like 1 or 2</p>



<a name="195626060"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195626060" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195626060">(Apr 28 2020 at 20:58)</a>:</h4>
<p>we can support "allocations"</p>



<a name="195626069"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195626069" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195626069">(Apr 28 2020 at 20:58)</a>:</h4>
<p>which are really just bits</p>



<a name="195626081"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195626081" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195626081">(Apr 28 2020 at 20:58)</a>:</h4>
<p>they have to be "interpreted" relative to some type</p>



<a name="195626113"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195626113" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195626113">(Apr 28 2020 at 20:59)</a>:</h4>
<p>i.e., <code>(2, 2)</code> and <code>struct Foo(i32, i32)</code> are the same at the <code>Allocation</code> level</p>



<a name="195626125"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195626125" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195626125">(Apr 28 2020 at 20:59)</a>:</h4>
<p>but quite distinct with respect to their type</p>



<a name="195626133"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195626133" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195626133">(Apr 28 2020 at 20:59)</a>:</h4>
<p>/me is remembering this right now ;)</p>



<a name="195626168"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195626168" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195626168">(Apr 28 2020 at 20:59)</a>:</h4>
<p>so yeah I think that for a constant value to be complete, it will need to carry its type along with it</p>



<a name="195626177"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195626177" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195626177">(Apr 28 2020 at 20:59)</a>:</h4>
<p>we may not <em>use</em> that type for much in <em>chalk</em></p>



<a name="195626228"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195626228" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195626228">(Apr 28 2020 at 21:00)</a>:</h4>
<p>but the aim is for chalk's definition of a constant and rustc's defintiion to be <em>the same thing</em> eventually</p>



<a name="195626271"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195626271" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195626271">(Apr 28 2020 at 21:00)</a>:</h4>
<p>which...they eventually will be</p>



<a name="195626306"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195626306" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Areredify <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195626306">(Apr 28 2020 at 21:00)</a>:</h4>
<p>it actually should be cheap to use because we can use <code>==</code> to compare types of two consts, right?</p>



<a name="195626335"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195626335" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Areredify <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195626335">(Apr 28 2020 at 21:01)</a>:</h4>
<p>Because they shouldn't have any binders or bound variables or anything</p>



<a name="195626522"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195626522" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195626522">(Apr 28 2020 at 21:02)</a>:</h4>
<p>that doesn't seem true</p>



<a name="195626531"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195626531" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195626531">(Apr 28 2020 at 21:02)</a>:</h4>
<p>e.g., <code>fn(&amp;u8)</code> is a valid constant type</p>



<a name="195626584"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195626584" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Areredify <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195626584">(Apr 28 2020 at 21:02)</a>:</h4>
<p>it is <span aria-label="scared" class="emoji emoji-1f628" role="img" title="scared">:scared:</span> ?</p>



<a name="195626599"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195626599" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195626599">(Apr 28 2020 at 21:03)</a>:</h4>
<p>I think so..</p>



<a name="195626646"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195626646" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195626646">(Apr 28 2020 at 21:03)</a>:</h4>
<div class="codehilite"><pre><span></span><code><span class="k">fn</span> <span class="nf">foo</span><span class="p">()</span><span class="w"> </span><span class="p">{</span><span class="w"> </span><span class="p">}</span><span class="w"></span>

<span class="k">const</span><span class="w"> </span><span class="n">X</span>: <span class="nc">fn</span><span class="p">()</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">foo</span><span class="p">;</span><span class="w"></span>

<span class="k">fn</span> <span class="nf">main</span><span class="p">()</span><span class="w"> </span><span class="p">{</span><span class="w"> </span><span class="p">}</span><span class="w"></span>
</code></pre></div>



<a name="195626676"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195626676" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195626676">(Apr 28 2020 at 21:03)</a>:</h4>
<p><a href="https://play.rust-lang.org/?version=stable&amp;mode=debug&amp;edition=2018&amp;gist=9736b4dae272c63e40670d0316c1abca" title="https://play.rust-lang.org/?version=stable&amp;mode=debug&amp;edition=2018&amp;gist=9736b4dae272c63e40670d0316c1abca">builds</a></p>



<a name="195626694"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195626694" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Areredify <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195626694">(Apr 28 2020 at 21:03)</a>:</h4>
<p>No, I mean consts that are used in types</p>



<a name="195626779"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195626779" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Areredify <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195626779">(Apr 28 2020 at 21:04)</a>:</h4>
<p>They have structural match and what not</p>



<a name="195626853"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195626853" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Areredify <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195626853">(Apr 28 2020 at 21:04)</a>:</h4>
<p>Wait</p>



<a name="195626867"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195626867" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Areredify <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195626867">(Apr 28 2020 at 21:04)</a>:</h4>
<p>Uhh</p>



<a name="195626975"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195626975" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195626975">(Apr 28 2020 at 21:05)</a>:</h4>
<p>eventually <code>Foo&lt;{X}&gt;</code> will presumably be allowed</p>



<a name="195627061"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195627061" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Areredify <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195627061">(Apr 28 2020 at 21:06)</a>:</h4>
<p>That is surprising to me, I really haven't thought about parametrizing types by functions</p>



<a name="195627106"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195627106" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Areredify <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195627106">(Apr 28 2020 at 21:06)</a>:</h4>
<p>you learn something new every day :P</p>



<a name="195627372"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195627372" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Areredify <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195627372">(Apr 28 2020 at 21:09)</a>:</h4>
<p>Hmm, that means we need to do a full tree-match of const types every time we do something with them?</p>



<a name="195627617"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.04.28/near/195627617" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E04.2E28.html#195627617">(Apr 28 2020 at 21:11)</a>:</h4>
<p>we have to equate the types as we would always do, presumably</p>



<hr><p>Last updated: Aug 07 2021 at 22:04 UTC</p>
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